Lighting fixture



March 13, 1934- c. H. OPPENHEIMER LIGHTING FIXTURE Filed Aug. 26. 1932 Patented Mar. 13, 1934 UNETE SATE PATENT OFICE assignor to Enterprise Electric Lighting Fixtures, Inc., Cleveland, Ohio, a corporation of Ohio Application August 26, 1932, Serial No. 630,565

2 Claims.

This invention relates to a full-indirect lighting fixture and has for its principal object to secure substantially uniformly diffused, prismatic illumination by theuse of a simple and efficient construction. A further object is to provide a fixture all the light from which will be thrown upwardly and one in which the points of equal intensity of illumination will form generally horizontal surfaces.

Other and more limited objects will become apparent from the following description when taken in connection with the accompanying drawing in which Fig. l is an elevational view and Fig. 2 is a section on the line 2-2 of Fig. 1.

Referring now to the accompanying drawing, the numeral 10 indicates a spun bronze canopy from which a bronze stem 11 projects downwardly and connects with a spun bronze shade holder 12. The stem 11 may pass through the canopy 10 and be supported from the ceiling 13 in the conventional manner. The stem 11 is tubular and afiords a passage for conductors adapted to supply electric current to a lamp or bulb within the fixture. Supported by the shade holder 12 is a prismatic glass globe 14. This globe has a smooth outer surface and an inner surface provided with vertically or substantially vertically extending prisms l5 and flares outwardly toward the bottom at an increasing rate. The outer surface of the globe 14 preferably corresponds to a surface of rotation produced by rotating a portion of a curve such as a circle, parabola or hyperbola about the vertical axis of the fixture. As is clear from the drawing, the narrowest part of the globe is at the top and the greatest diameter is at the bottom. By the use of the vertically extended prisms 15 on the inside of the globe 14 I am able to secure a breaking up of the spectrum which causes the light of different wave lengths to disperse fanwise in a substantially horizontal direction. Light proceeding from the filament of the bulb 16 will be spread horizontally by the prisms at the same time being caused to converge vertically to some extent by reason of the curvature of the globe 14. The result is that the points of equal illumination form generally horizontal surfaces and illuminate the ceiling more or less evenly and without zones of excessive brilliancy. It may be stated that the region of the ceiling immediately surrounding the fixture is somewhat less brilliantly illuminated than the remainder but this does not prevent the general effect described.

Secured to the globe 14 by means of a ring 17 is an opaque bowl 18. This bowl may be of spun iron finished inside and outside with fused porcelain enamel preferably white inside and tinted outside to give the desired decorative effect. The lamp 16 is positioned with its filament somewhat below the upper edge of the ring 1'7 whereby to cast the light rays upwardly at a slight angle. The positioning of the filament is not sharply critical and considerable leeway may be allowed without destroying the 66 superior results. A small power bulb 19 for dim lighting may be positioned as near as possible to the axis of the fixture and energized by a separate circuit. The fused white porcelain finish on the inside of the bowl 18 affords a reflect- 70 ing surface whereby to direct the downward light rays upwardly through the globe l i. By the use of the fully opaque bowl 18 I am able to secure the full advantage of the prismatic glass globe 14 and to distribute the light in such manner that the loci of isoluminous points are generally horizontal for a considerable distance from the fixture.

While I have shown and described the preferred embodiment of my invention, I wish it understood that I am not limited to the details shown and described except in accordance with the spirit and scope of the appended claims.

Having thus described my invention, what I claim is:

l. A full-indirect lighting fixture comprising an upper, globe portion made of prismatic glass and a lower, opaque bowl portion adjacent thereto, said globe fiaring from the top toward the bottom at an increasing rate and the prisms extending substantially vertically.

2. A full-indirect lighting fixture comprising an upper, globe portion made of prismatic glass and a lower, opaque bowl portion adjacent thereto, said globe flaring from the top toward the bottom at an increasing rate and the prisms extending substantially vertically, and means for supporting an electric bulb with its filament within said bowl and substantially on the center line of the fixture.

CHARLES H. OPPENHEIMER. 

